Summary

Bariatric surgery is an effective therapy for obesity but is associated with long-term complications such as dumping syndromes and nutritional deficiencies. We report a case of a 26-year-old caucasian female, with history of morbid obesity and gestational diabetes (GDM), who became pregnant 4 months after Roux-en-Y bypass surgery. She developed GDM during subsequent pregnancy, which was initially managed with metformin and insulin. Nocturnal hypoglycaemia causing sleep disturbance and daytime somnolence occured at 19 weeks of pregnancy (19/40). Treatment with rapid-acting carbohydrates precipitated further hypoglycaemia. Laboratory investigations confirmed hypoglycaemia at 2.2 mmol/L with appropriately low insulin and C-peptide, intact HPA axis and negative IgG insulin antibodies. The patient was seen regularly by the bariatric dietetic team but concerns about compliance persisted. A FreeStyle Libre system was used from 21/40 enabling the patient a real-time feedback of changes in interstitial glucose following high or low GI index food intake. The patient declined a trial of acarbose but consented to an intraveneous dextrose infusion overnight resulting in improvement but not complete abolishment of nocturnal hypoglycaemia. Hypoglycaemias subsided at 34/40 and metformin and insulin had to be re-introduced due to high post-prandial blood glucose readings. An emergency C-section was indicated at 35 + 1/40 and a small-for-gestational-age female was delivered. There have been no further episodes of hypoglycaemia following delivery. This case illustrates challenges in the management of pregnancy following bariatric surgery. To our knowledge, this is the first use of FreeStyle Libre in dumping syndrome in pregnancy following bariatric surgery with troublesome nocturnal hypoglycaemia.

Learning points:

Bariatric surgery represents the most effective treatment modality in cases of severe obesity. With increasing prevalence of obesity, more people are likely to undergo bariatric procedures, many of which are women of childbearing age.

Fertility generally improves after bariatric surgery due to weight reduction, but pregnancy is not recommended for at least 12–24 months after surgery. If pregnancy occurs, there are currently little evidence-based guidelines available on how to manage complications such as dumping syndromes or gestational diabetes (GDM) in women with history of bariatric surgery.

Diagnosis of GDM relies on the use of a 75 g oral glucose tolerance test (OGTT). The use of this test in pregnant women is not recommended due to its potential to precipitate dumping syndrome. Capillary glucose monitoring profiles or continuous glucose monitoring (CGM) is being currently discussed as alternative testing modalities.

As the CGM technology becomes more available, including the recently introduced FreeStyle Libre Flash glucose monitoring system, more pregnant women, including those after bariatric surgery, will have access to this technology. We suggest urgent development of guidelines regarding the use of CGM and flash glucose monitoring tools in these circumstances and in the interim recommend careful consideration of their use on a case-to-case basis.

Summary

Adrenacarcinomas are rare, and hypoglycemic syndrome resulting from the secretion of insulin-like growth factor II (IGF-II) by these tumors have been described infrequently. This study describes the case of a young woman with severe persistent hypoglycemia and a large adrenal tumor and discusses the physiopathological mechanisms involved in hypoglycemia. The case is described as a 21-year-old woman who presented with 8 months of general symptoms and, in the preceding 3 months, with episodes of mental confusion and visual blurring secondary to hypoglycemia. A functional assessment of the adrenal cortex revealed ACTH-independent hypercortisolism and hyperandrogenism. Hypoglycemia, hypoinsulinemia, low C-peptide and no ketones were also detected. An evaluation of the GH–IGF axis revealed GH blockade (0.03; reference: up to 4.4 ng/mL), greatly reduced IGF-I levels (9.0 ng/mL; reference: 180–780 ng/mL), slightly reduced IGF-II levels (197 ng/mL; reference: 267–616 ng/mL) and an elevated IGF-II/IGF-I ratio (21.9; reference: ~3). CT scan revealed a large expansive mass in the right adrenal gland and pulmonary and liver metastases. During hospitalization, the patient experienced frequent difficult-to-control hypoglycemia and hypokalemia episodes. Octreotide was ineffective in controlling hypoglycemia. Due to unresectability, chemotherapy was tried, but after 3 months, the patient’s condition worsened and progressed to death. In conclusion, our patient presented with a functional adrenal cortical carcinoma, with hyperandrogenism associated with hypoinsulinemic hypoglycemia and blockage of the GH–IGF-I axis. Patient’s data suggested a diagnosis of hypoglycemia induced by an IGF-II or a large IGF-II-producing tumor (low levels of GH, greatly decreased IGF-I, slightly decreased IGF-II and an elevated IGF-II/IGF-I ratio).

Learning points:

Hypoglycemyndrome resulting from the secretion of insulin-like growth factor II (IGF-II) by adrenal tumors is a rare condition.

Hypoinsulinemic hypoglycemia associated with hyperandrogenism and blockage of the GH–IGF-I axis suggests hypoglycemia induced by an IGF-II or a large IGF-II-producing tumor.

Hypoglycemia in cases of NICTH should be treated with glucocorticoids, glucagon, somatostatin analogs and hGH.

Summary

Pancreatic neuroendocrine tumours (pNETs) secreting proglucagon are associated with phenotypic heterogeneity. Here, we describe two patients with pNETs and varied clinical phenotypes due to differential processing and secretion of proglucagon-derived peptides (PGDPs). Case 1, a 57-year-old woman presented with necrolytic migratory erythema, anorexia, constipation and hyperinsulinaemic hypoglycaemia. She was found to have a grade 1 pNET, small bowel mucosal thickening and hyperglucagonaemia. Somatostatin analogue (SSA) therapy improved appetite, abolished hypoglycaemia and improved the rash. Case 2, a 48-year-old male presented with diabetes mellitus, diarrhoea, weight loss, nausea, vomiting and perineal rash due to a grade 1 metastatic pNET and hyperglucagonaemia. In both cases, plasma levels of all measured PGDPs were elevated and attenuated following SSA therapy. In case 1, there was increased production of intact glucagon-like peptide 1 (GLP-1) and GLP-2, similar to that of the enteroendocrine L cell. In case 2, pancreatic glucagon was elevated due to a pancreatic α-cell-like proglucagon processing profile. In summary, we describe two patients with pNETs and heterogeneous clinical phenotypes due to differential processing and secretion of PGDPs. This is the first description of a patient with symptomatic hyperinsulinaemic hypoglycaemia and marked gastrointestinal dysfunction due to, in part, a proglucagon-expressing pNET.

Summary

Approximately 35% of the pancreatic neuroendocrine tumors (pNETs) are functional, the most common of which is an insulinoma. Rarely can initially nonfunctioning tumor undergo biological transformation to a hormone-secreting tumor with subsequent changes in the clinical picture. We present here three unique patients with long-standing pNETs who developed life-threatening hyperinsulinemic hypoglycemia along with tumor progression. In two of the patients, everolimus (Afinitor) was administered in an attempt to control both tumor growth and hypoglycemia. In two cases everolimus therapy resulted in the abolishment of hypoglycemia and induced significant tumor regression; however these beneficial responses were transient. These cases highlight the exceptional ability of pNETs to change biological behavior in parallel with disease progression. Our experience concurs with recently published studies demonstrating the utility of everolimus for the control of both hypoglycemia and tumor progression.

Learning points

Nonfunctional pNET can gain new features such as insulin secretion with related morbidity.

Gain of function in a previously nonfunctional pNET signifies tumor progression and is usually associated with poor prognosis.

Everolimus proved to be a viable treatment for hypoglycemia in insulinoma patients and was also proven highly effective in the patients presented here.

As disease progresses, the effect of everolimus on hypoglycemia wanes. We report for the first time the development of hypoglycemia during everolimus treatment.